[PATCH net] udp: unbreak build lacking CONFIG_XFRM

[Paolo Abeni]

We must use pre-processor conditional block or suitable accessors to
manipulate skb->sp elsewhere builds lacking the CONFIG_XFRM will break.

Fixes: dce4551cb2ad ("udp: preserve head state for IP_CMSG_PASSSEC")
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
 net/ipv4/udp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index d243772f6efc..fac7cb9e3b0f 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1786,7 +1786,7 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct 
sk_buff *skb)
         * the IP options and the cmsg flags, elsewhere can we clear all
         * pending head states while they are hot in the cache
         */
-       if (likely(IPCB(skb)->opt.optlen == 0 && !skb->sp))
+       if (likely(IPCB(skb)->opt.optlen == 0 && !skb_sec_path(skb)))
                skb_release_head_state(skb);
 
        rc = __udp_enqueue_schedule_skb(sk, skb);
-- 
2.13.3